The effect of hematocrit on the efficiency of hemodialysis in cases of chronic renal failure.

Twenty patients of chronic renal failure were evaluated to study the effect of increase in hematocrit (Hct) on the efficiency of hemodialysis. All the patients were subjected to two hemodialysis of identical duration with an interdialytic interval of 48 hours. All were anemic with a mean hemoglobin of 6.73 gm% and a hematocrit of 22.2%. Hematocrit was raised to a mean of 32.02% following transfusion of 2 units (600-700 ml) of whole blood (p < 0.001) in the interdialytic interval. Blood clearances (Kb). Dialysate clearance (Kd), fractional decrement and Kt/V ratio of solutes (urea, creatinine and phosphates) were calculated during both the dialysis and compared with each other. Kt/V of urea decreased from 1.0589 +/- 0.24 to 0.89 +/- 0.15 (p < 0.001), and that of creatinine 1.003 +/- 0.19 to 0.832 +/- 0.009 (p < 0.001) and phosphates 0.992 +/- 0.16 to 0.826 +/- 0.006 (p < 0.001) and it showed a negative correlation with rise in hematocrit. It was significant for creatinine and phosphates and insignificant for urea, suggesting thereby that the efficiency of dialysis decreased with increase in hematocrit. This is important in view of under dialysis in patients of normal or near normal hematocrit and suggests the need for modification of dialysis prescription in such situations.